Blasting block connector

ABSTRACT

A connector block having an elongated body with an end wall at one end. A resilient, cantilever arm extends from one side of the end wall over the wall to the other side of the wall and terminates in a free end at the other side of the end wall. The arm is spaced from the outer face of the end wall to define, with the outer face, a slot that snugly receives signal lines. The cantilevered arm is tapered in thickness toward its free end in a manner to have the end wall curl back over itself when the block is used by exploding a detonator carried by the block.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention is connected toward an improved connector block.

[0003] 2. Description of the Related Art including Information Disclosed under CFR §§1.97-1.99

[0004] A connector block is used in blasting operations to connect a detonator to at least one signal transmission line. An example of such a block is shown in U.S. Pat. No. 5,703,319.

[0005] A connector block has an elongated body member for holding a detonator therein with the explosive end of the detonator at one end of the block. Means are provided at this one end of the block for holding signal transmission lines adjacent the explosive end of the detonator. Several of the new connector blocks use a cantilevered arm on the end wall of the block at the one end to hold the signal lines adjacent to the explosive end of the detonator at the one end wall of the block. The signal lines are located in a narrow space or slot formed between the arm and the one end wall of the block and are inserted into that space through an entrance between the free end of the arm and the end wall. The slot is shaped and sized to hold the lines quite firmly, closely adjacent to the end of the detonator.

[0006] These known connector blocks can be dangerous however when detonated. Often the cantilevered arm will blow off the block when the detonator is detonated and the arm, as a small missile, could injure someone.

SUMMARY OF THE INVENTION

[0007] It is the purpose of the present invention to provide connector blocks of the type employing a cantilevered arm to hold the signal lines that are safer in operation than the known blocks. More particularly, it is the purpose of the present invention to provide connector blocks in which the cantilevered arm remains attached to the block when detonated.

[0008] In accordance with the present invention there is provided a connector block having a cantilevered arm at least the front portion of which is tapered from a thin front end to a thicker middle section. As a result of this construction, the cantilevered arm peels or rolls back from its free front end toward its supported rear end, away from the end wall of the block, instead of being blown off the connector block when the detonator is detonated. With the arm remaining attached to the block during detonation, the block is much safer in use.

[0009] The invention is particularly directed toward a connector block having an elongated body, the body having an end wall at one end, the end wall having an outer face. An opening in the end wall extends through the end wall to the outer face. The body supports a detonator with a leading explosive end of the detonator extending into the opening in the end wall and at least close to the outer face of the end wall. A resilient, cantilever arm extends from one side of the end wall over the outer face of the end wall to the other side of the end wall and terminates in a free end at the other side of the end wall. The arm is spaced from the outer face to define, with the outer face, a slot that snugly receives signal lines so as to locate the signal lines adjacent the opening. The free end of the arm and the end wall form an entrance to the slot that is narrower than the slot. The cantilevered arm is tapered in thickness, from a point spaced along its length from its connection to the end wall determined by where the arm will curl rearwardly over itself, instead of separating from the end wall, when the detonator is exploded, to adjacent its free end where it is thinnest.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is perspective view of a known connector block;

[0011]FIG. 2 is a cross-section view of the known block taken along line 2-2 in FIG. 1;

[0012]FIG. 3 is a detail view of the entrance to the slot in the known block;

[0013]FIG. 4 is a perspective view of a known detonator;

[0014]FIG. 5 is a view similar to FIG. 2 but with the known detonator and signal lines mounted on the known block;

[0015]FIG. 6 is a view similar to FIG. 2 showing the improved connector block; and

[0016]FIG. 7 is a view similar to FIG. 6 but showing the block after the detonator has exploded.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A prior art connector block 1, as shown in FIGS. 1 and 2, has an elongated body 3 with side walls 5 joined by a bottom wall 7 defining an open, elongated channel 9. One end of the body 3 is closed by an end wall 11. The other end of the body 3 could also be partly closed by a second end wall 13 if desired. The channel 9 holds a detonator DE as will be described. The detonator DE can rest on the bottom wall 7 of the body 3. Preferably, a detonator support 15 is provided on the bottom wall 7 and supports the detonator DE in the channel 9. A cover 17 can be provided to close the body 3. The cover 17 can be attached to the body 3 to be on one side of the body when not in use. The cover 17, in use, rests on the top free edges 19 of the side walls 5. Cooperating locking means (not shown) are provided on the cover 17 and the side walls 5 of the body 3 for locking the cover 17 to the body 3 when in use. The cover 17 can also have retaining means 20 on its bottom surface 21 for cooperating with the detonator DE to retain the detonator in place within the body 3 as will be described. The end wall 11 has a cylindrical opening 23 there through which opening is aligned with the detonator support 15.

[0018] The outer surface 31 of the end wall 11 has a semicylindrical surface portion 33, generally overlying the opening 23 and extending across the height of the end wall 11. This curved surface portion 33 is transverse to the longitudinal axis 35 of the opening 23. A pair of stop members 37 within the opening 23 partially close the opening adjacent the surface portion 33, the stop members 37 integral with the end wall 11.

[0019] The known connector block 1 includes a resilient, cantilevered arm 41 extending from one side 43 of the end wall 11 over and across its outer surface 31, substantially covering the outer surface 31. The arm 41 has a main body portion 45, the length of which constitutes a substantial portion of the length of the arm, and which extends from the one side 43 of the end wall 11. The main body portion 45 is of the same thickness over its length and is spaced from the outer surface 31 of the end wall 11 and curved over the semicylindrical surface portion 33 in a manner to form a narrow slot 47 which slot is of uniform width over at least a major portion of its length. The arm 41 has a free end portion 49 extending from the main body portion 45 of the arm 41, which tapers to a point.

[0020] The free end portion 49 of the arm 41 forms a v-shaped entrance 51 with an entrance portion 53 of the outer surface 31 of the end wall 11 adjacent the other side 55 of the end wall 11 as shown in detail in FIG. 3. The entrance 51 provides access into the slot 47. Preferably, the free end portion 49 of the arm 41 has its inner surface 57 angled outwardly forming one slanted side of the entrance 51. The entrance portion 53 on the end wall 11 has an inwardly angled surface 59 forming the other slanted side of the entrance 51. The end of the slot 47 near the other side 55 of the end wall 11 undercuts the entrance portion 53 forming a resilient finger 61 that, with the free end portion 49 of the resilient arm 41, substantially closes the entrance 51. This type of connector block is known.

[0021] The known block 1 is used with a detonator DE. The detonator DE, as shown in FIG. 4, has a casing C with a leading explosive end LE and an open trailing end TE. The casing C is preferably cylindrical in shape although it could have other shapes. The open trailing end TE is closed by a resilient bushing B through which a detonator signal line DSL is passed into the casing C. The casing C is crimped about the bushing B as shown at CR. At least one crimp and preferably two are employed. Detonators of this type are well known.

[0022] To use the block 1, the detonator DE in placed in the channel 9 of the block 1 with its leading end LE inserted into the opening 23 in the end wall 11 and tight against the stops 37 as shown in FIG. 5. The stops 37 serve to locate the explosive end LE of the detonator DE relative to the semi-cylindrical surface 33 of the end wall 11. The casing C rests on the support 15 in the channel 9 and the detonator signal line DSL extends rearwardly out of the body 3 through a slot 61 in the other end wall 13. The cover 17 is used to close the body 3 and retain the detonator DE tight against the stops 37 and the support 15 with the retaining means 19 on the bottom of the cover 17. The retaining means 19 partly encircle one of the crimps CR on the detonator casing C preventing both lateral and longitudinal movement of the detonator.

[0023] The signal lines SL are passed through the entrance 51 into the slot 47 between the resilient finger 61 and the free end portion 49 of the resilient arm 41. The slot 47 is just wide enough to snugly receive the signal lines SL which lines, when in the slot 47, extend transverse to the longitudinal axis 35 of the opening 23. The signal lines SL are placed in the slot 47 through the entrance 51 one at a time. The resilient arm 41 helps hold the signal lines SL in place within the slot. The signal lines SL lie closely adjacent to the leading explosive end LE of the detonator DE, all about the same distance therefrom. Detonation of the detonator DE sends a signal through each signal line SL.

[0024] In accordance with the present invention, the cantilevered arm 41′ of the connector block 1′, as shown in FIG. 6, is modified to ensure that it remains with the body 3′ of the block when the detonator DE is detonated. To this end, the main body portion 45′ of the arm 41′ is modified to taper in thickness, from a point spaced from its connection to the end wall determined by where the free end of the arm will curl back on itself when the detonator is exploded, to the free end portion 49′. Preferably, the main body portion 45′ of the arm 41′ is modified to taper in thickness at least from about its mid-point 71, at about the longitudinal axis 35′ of the opening 23′ in the end wall 11′, to the free end portion 49′, tapering from a thick cross-section at the mid-point 71 to a thin cross-section adjacent the free end portion 49′. The free end portion 49′ is also modified to have a thickness at its thick end equal to the thickness at the thin end 73 of the body portion. The tapered, forward portion 75 of the main body 45′ of the arm 41′ allows the arm to curl backward, as shown in FIG. 7, when the detonator DE is exploded, starting from its free end portion 49′, instead of being blown off. Thus the arm 41′ stays connected to the block during detonation making the block much safer in use. The tapering of the arm 41′ is done in a manner to leave the thickness of the slot 47′ unchanged.

[0025] If desired, the main body 45′ of the arm can be tapered back from its free end portion 49′ to a point close to the location where the arm is connected to the end wall. The arm would be tapered for about three quarters of its length in this case provided a longer tapered forward portion 75 of the arm 41′ making it still easier to curl the arm backward on itself during detonation.

[0026] The cantilevered arm 41 has been described as being resilient. The arm 41 could, in some cases, be rigid rather than springy with the arm slightly squeezing the signal lines SL to securely hold them in the slot 47 and with the resilient finger 61 in the entrance 51 designed to allow passage of the signal lines SL into the slot without movement of the arm 41.

[0027] While one form of known connecting block has been described, other similar types of known blocks, using a cantilevered arm to hold the signal lines, can be employed, but with the arm modified according to this invention. The cantilevered arm and entrance is designed according to the present invention to securely retain all the signal lines in position within the slot adjacent the detonator, while still allowing entrance of the lines into the slot and also ensuring that the arm is tapered in a manner allowing it to curl starting from its front end when the detonator is exploded. 

I claim:
 1. A connector block having an elongated body, the body having an end wall at one end, the end wall having an outer face; an opening in the end wall extending through the end wall to the outer face; the body adapted to support a detonator with a leading explosive end of the detonator extending into the opening in the end wall and at least close to the outer face of the end wall; a cantilever arm extending from one side of the end wall over the outer face of the end wall to the other side of the end wall and terminating in a free end at the other side of the end wall; the arm spaced from the outer face to define, with the outer face, a slot that snugly receives signal lines so as to locate the signal lines adjacent the opening; the free end of the arm and the end wall forming an entrance to the slot; the cantilevered arm tapered in thickness, from a point spaced along its length from its connection to the end wall determined by where the arm will curl rearwardly over itself rather than separate from the end wall when the detonator is exploded, to adjacent its free end where it is thinnest.
 2. A connector block as claimed in claim 1 wherein the cantilevered arm is tapered from at least the center of the arm, where the longitudinal axis of the opening intersects the arm, to adjacent its free end where it is thinnest.
 3. A connector block as claimed in claim 1 wherein the cantilevered arm is resilient.
 4. A connector block as claimed in claim 2 wherein the cantilevered arm is resilient
 5. A connector block as claimed in claim 1 wherein the portion of the slot that receives the signal lines is of uniform width.
 6. A connector block as claimed in claim 2 wherein the portion of the slot that receives the signal lines is of uniform width.
 7. A connector block as claimed in claim 3 wherein the portion of the slot that receives the signal lines is of uniform width.
 8. A connector block as claimed in claim 4 wherein the portion of the slot that receives the signal lines is of uniform width.
 9. A connector block as claimed in claim 1 wherein the outer face of the end wall is curved to have a generally semicircular portion extending toward the arm, the portion centrally located with respect to the opening, the arm curved to follow the curved portion to provide a slot of substantially uniform width.
 10. A connector block as claimed in claim 2 wherein the outer face of the end wall is curved to have a generally semicircular portion extending toward the arm, the portion centrally located with respect to the opening, the arm curved to follow the curved portion to provide a slot of substantially uniform width.
 11. A connector block as claimed in claim 3 wherein the outer face of the end wall is curved to have a generally semicircular portion extending toward the arm, the portion centrally located with respect to the opening, the arm curved to follow the curved portion to provide a slot of substantially uniform width.
 12. A connector block as claimed in claim 4 wherein the outer face of the end wall is curved to have a generally semicircular portion extending toward the arm, the portion centrally located with respect to the opening, the arm curved to follow the curved portion to provide a slot of substantially uniform width. 